The present invention relates to an output circuit for an engine control device and a method of monitoring such a circuit.
The present invention relates more particularly to motor vehicles (cars, trucks, motorcycles, etc.) equipped with an internal combustion or electric engine.
A modern engine for a motor vehicle is usually managed, at least partially, by an engine control device, or digital engine control device also known under the abbreviation ECU (for ‘Engine Control Unit’). This control device chiefly comprises an electronic computer, or microcontroller, which ensures the digital processing of signals that it receives from various sensors and which controls components such as, for example, the corresponding actuators. The control device generally comprises one (or more) intelligent output circuit(s) which drive outputs connected to said components. The output signals are controlled by each output circuit according to control signals received from the computer.
For each component, making a diagnosis of the connection to the component is known for checking the correct operation of the output circuits. The diagnostic function is generally performed regularly, at as high a frequency as possible. Each time that this diagnosis is implemented, the result, positive or negative, is transmitted to a management device which centralizes all the results of all the diagnoses carried out. The diagnosis is performed by the microcontroller which regularly sends diagnostic requests to the corresponding output circuit. The latter then responds to the microcontroller. The response thus provided is used to determine whether or not the output circuit concerned is operating correctly.